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Biomedical subjects

F Lampert

Publications and source records attributed to F Lampert.

At least 55 records · Page 3Linked to original sources
PubMed1997

Disseminated neuroblastomas under 1 year of age: cell biology and prognosis.

Tumor specimens of 203 infants with neuroblastomas of different clinical stages-registered in successive multicenter clinical trials of the German Society of Pediatric Oncology-could be examined for N-myc amplification, chromosome 1-ploidy and-structure, CD44 std. expression (in tumor tissue, and also in patient's sera). Eighty-seven (= 43%) of these infants had a non-localized, disseminated neuroblastoma, mainly involving sympathetic nerve tissue, lymph nodes, liver, skin, bone marrow and bones (46 patients were classified into the 4 group, 41 patients in the true 4 group). If the clinical classification between stage 4 and stage 4s was neglected, then 17 of these infants (= 20%) had N-myc amplification (4-64 copies) with 16 already dead. Seven of 9 examined patients with true stage 4- had chromosome 1p aberrations (with N-myc amplification in 5), and among the dead there were 2 with CD44 negative expression. In another series, serum CD44 std. was measured by ELISA, and the highest (significantly different) Kruskal-Wallis mean rank values (147.8) were found in infants (n = 6) with stage 4s compared to the low mean-rank-value of 71.9 in patients with stage 4 (n = 65). Stage 1-3 patients (n = 42) had values of 99.8-88.6. Thus, infants with disseminated neuroblastomas, showing non-diploidy, normal chromosome 1p structure, non-N-myc amplification and high CD44 std. expression in tumor tissue, and also high CD44 std. values in serum, will have the highest chance of survival due to tumor-non-progression. On the other hand, N-myc amplification in the tumor cells was found to be characteristic for stage 4s neuroblastoma patients with tumor progression (n = 6). Therefore, 4s neuroblastoma-patients with N-myc amplified tumors should be aggressively treated like true stage 4 tumor patients.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

Treatment of hypersensitive teeth using neodymium:yttrium-aluminum-garnet lasers: a comparison of the use of various settings in an in vivo study.

The spectrum of the methods available to treat hypersensitive teeth is very great. The chances for success in the use of these different therapies are equally variable. Faced with the already successful effort of the Nd:YAG laser in the treatment of exposed tooth necks, the effectiveness of the use of different settings of the Nd:YAG laser on exposed dentine was examined in this clinical study. In the case of comparison of the therapy success of the laser settings amongst one another, no significant difference could be found. This leads us to a conclusion, that laser irradiation is therapeutically effective at very low settings.

Adult↗
PubMed1997

The efficiency of root canal disinfection using a holmium:yttrium-aluminum-garnet laser in vitro.

The aim of the present study was to determine the bactericidal effect of a holmium:yttrium-aluminum-garnet (Ho:YAG) laser on root canals in vitro. The efficiency of different laser settings was compared. The in vitro examinations revealed extensive bacterial reduction in extracted, endodontically prepared teeth that had been incubated with Streptococcus faecalis with the most favorable results at a setting of 5 Hz and 2 W. In average, 99.98% of the bacteria injected in the root canal could be eliminated. Considering this bactericidal effect, the application of the Ho:YAG laser in root canal treatment appears to be very efficient.

Dental Pulp Cavity↗
PubMed1997

Transcription of hepatitis B virus in peripheral blood mononuclear cells from persistently infected patients.

Hepatitis B virus (HBV) has been reported to exist in peripheral blood mononuclear cells (PBMC), but it is not clear whether it replicates there. A precondition for replication should be the formation of covalently closed viral DNA and transcription of all essential viral mRNAs. The mRNAs of HBV form a nested box with common 3' ends. In order to detect even low levels of potential replication, we developed a quantitative reverse transcription-PCR method for detection of a smaller HBV mRNA species in the presence of the larger ones. All three highly viremic patients tested so far had mRNAs for the large and the small surface proteins and the X protein of the virus within PBMC but not in the virus from their sera. Furthermore, we detected by PCR covalently closed viral DNA in their PBMC. These data suggest that HBV may be not only taken up but also replicated by mononuclear blood cells and that these cells may be an extrahepatic site of viral persistence. X mRNA was detected in the largest amount. Possibly, X protein interferes with functions of the mononuclear cells during the immune response against the virus.

Adult↗
PubMed1997

Modified partial-coverage ceramics for anterior teeth: a new restorative method.

A new restorative method, (the Edge Up technique) enables the correction of defects in the anterior tooth area with a maximum preservation of tooth substance. The basis of this technique is a special preparation method (a circular extended shoulder preparation in the enamel or an angle preparation) and a preparation kit matched to the peculiarities of this preparation technique.

Dental Porcelain↗
PubMed1996

[Synopsis of unbalanced chromosome aberrations in neuroblastoma by comparative genomic hybridization].

Neuroblastoma is the most frequent extracranial solid tumor of early childhood. Histologically and genetically, neuroblastoma represents a heterogeneous group of tumors with significant differences in clinical behavior. In the past, several different characteristic chromosomal aberrations of neuroblastoma have been described, of which a deletion on chromosome 1p and N-myc amplification have been shown to be of major prognostic significance. However, the role of various other nonrandom DNA imbalances in tumor development and progression needs to be clarified. Taking advantage of the recently established comparative genomic hybridization (CGH), we show that this method is able to accurately detect chromosomal imbalances of known prognostic impact. As CGH gives a comprehensive picture of genetic imbalances in just one experiment, it additionally sheds light on other abnormalities of possible prognostic relevance. We therefore recommend further use of this method not only in the field of research but also for the purpose of genetic routine diagnostics in neuroblastoma.

Child↗
PubMed1996

Penetration of etching agents and its influence on sealer penetration into fissures in vitro.

OBJECTIVES: This study was designed to assess: 1) the ability of several commercially available and laboratory-made acid etchants to penetrate occlusal fissures when used for pit and fissure sealing, and 2) the influence of adding a surfactant to the etchant on penetration of the sealer. Viscosity, surface tension and contact angle to enamel of the etchants were determined for each treatment, and these properties were related to the etchant's ability to penetrate fissures. METHODS: Penetration was assessed in an acrylic fissure model having a deep-narrow fissure using a microscope and a chronometer. Penetration depth was expressed as percentage of total fissure depth and was measured in intervals up to 90 s. Commercially available etching agents with different viscosities and two solutions of phosphoric acid (37%), one with and one without a surfactant, were tested. The etch pattern obtained on the fissure wall enamel of extracted teeth with some of these products was evaluated using scanning electron microscopy. Eventually, the penetration depths of a composite sealer in fissures treated with a conventional etchant were compared to those after application of a surfactant-containing etchant on sections of extracted teeth. RESULTS: None of the commercially available etchants studied were able to penetrate farther than 17% of the total fissure depth in the fissure model. The surfactant-containing etchant showed complete penetration within about 1 min and had a significantly lower surface tension and contact angle than the other products tested. Only the surfactant-containing etchant could produce a retentive pattern on the entire wall enamel of the fissure with the exception of locations blocked by debris and plaque. Fissures treated with this product prior to sealing showed a significantly deeper penetration of the sealer in deep-marrow fissures. SIGNIFICANCE: Surfactant-containing etchants with a low viscosity can penetrate completely into fissures and can produce an increased retentive and wettable surface which significantly increased sealant penetration into deep fissures.

Acid Etching, Dental↗
PubMed1996

Long-term clinical evaluation of endodontically treated teeth by Nd:YAG lasers.

It was possible for the patients to avoid surgical intervention in a number of complicated periapical endodontic situations by means of Nd:YAG laser-assisted sterilization. A WSR has only very good primary results and the long-term successes are very limited. Once a lesions has healed in the manner explained in this study, in other words, with regeneration of the periapical anatomy, there is a very good long-term prognosis. Laser technology is an instrument whose overall effects represent a decisive improvement in the efficiency of conservative endodontic treatment in fields that were previously outside our sphere of influence.

Bacteria↗
PubMed1996

Bactericidal effect of the Nd:YAG laser in in vitro root canals.

The current study investigates the bactericidal effect of a pulsed Nd:YAG laser on 40, classically prepared, in vitro root canals under standardized conditions. The output of the device including quartz fiber was measured before and after every treatment to exclude any technical faults. A 300-micron fiber was used for the anterior teeth and a 200-micron fiber for the posterior teeth. The Enterococcus faecalis bacteria, as gram-positive cocci, display a heat tolerance in the upper range of the bacilli that can be found in the endodontology and the concentration also reflects the in vivo conditions. The results are quoted in "log kills" in accordance with the work of Rooney et al. On average, 99.91% of the Enterococcus faecalis bacteria injected into the root canals prepared in vitro could be eliminated (97.12% minimum, 99.9997% maximum). This setup suggests that the bactericidal effect of laser therapy in the framework presented here can also be achieved in vivo in clinical cases.

Colony Count, Microbial↗
PubMed1996

The recurrence patterns of stages I, II and III neuroblastoma: experience with 77 relapsing patients.

BACKGROUND: Recurrences of neuroblastoma Evans' stage I-III are infrequent events and the types of its progression have rarely been reported. Therefore, we investigated the patterns of progression in a large series of patients with long follow-up. PATIENTS AND METHODS: The sites of relapse and time to progression and death of 381 consecutive patients in three cooperative trials (NB 79, 82, 85) with follow-up of 5-16 years were analysed. The Southern blot technique was used for N-myc investigation of tumor tissue. RESULTS: Of the 77 relapsing patients, 41 (53%) had local and 36 (47%) systemic recurrences. The relapses occurred in 9 of 76 stage I patients (6 local/3 systemic), in 4 of 82 stage II (1 local/3 systemic) and 64 of 223 stage III neuroblastoma (34 local/30 systemic) patients. The main sites of distant metastasis were bone marrow (41%), lymph nodes (39%) and bone (37%). The median transition time from localised to metastatic neuroblastoma was 13 months and the outcome as poor (overall survival 9 +/- 5%) as that of the primary metastatic disease (14 +/- 3%). Fifty-three children died of tumor progression and 15 patients of treatment-related complications or other non-tumor conditions. The median age at diagnosis was 43 months for the group with systemic relapse compared to 19 months with only local and 10 months without recurrences (p < 0.001). Elevated serum LDH levels at first diagnosis were seen in 81% with metastatic, in 55% with local and in 33% with no tumor progression (p < 0.001). N-myc amplification was found in 4/14 with local and in 6/12 with metastatic recurrences. CONCLUSION: The high incidence of systemic relapse and the long transition time suggest that transition from localised to metastatic neuroblastoma is not an uncommon pathway.

Adolescent↗
PubMed1996

PCR reaction and dot-blot hybridization to monitor the distribution of oral pathogens within plaque samples of periodontally healthy individuals.

The purpose of this study was to determine the distribution of the putative periodontal pathogens Prevotella intermedia, Prevotella nigrescens, the three oral Capnocytophaga species (C. ochracea, C. sputigena, C. gingivalis), as well as Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in plaque samples of periodontally healthy individuals. We chose a newly developed 16S rDNA directed polymerase chain reaction (PCR) and a previously described dot-blot hybridization assay to detect, differentiate, and quantify these bacteria directly in clinical samples. The subjects of these investigations were 66 sulcus fluid samples from 17 children (ages 3 to 5) attending a kindergarten, 48 sulcus fluid samples from 12 children (ages 9 and 10) from a primary school, and 25 subgingival plaque samples isolated from 6 different periodontally healthy dental students (ages 24 to 27). We were able to demonstrate the presence of P. nigrescens in 54 (kindergarten: 5; primary school: 33; students: 16) samples by PCR and quantified it by dot-blot hybridization. In addition, we found C. ochracea in 12 (kindergarten: 2; primary school: 10) samples by PCR reaction only. The other tested bacterial species were absent by the methods used. Furthermore we confirmed the specificity of our P. nigrescens-PCR in selected samples by enzyme electrophoresis.

Adult↗
PubMed1996

Incidence and clinical outcome of children with BCR/ABL-positive acute lymphoblastic leukemia (ALL). A prospective RT-PCR study based on 673 patients enrolled in the German pediatric multicenter therapy trials ALL-BFM-90 and CoALL-05-92.

A variety of oncogenes are activated by specific chromosomal translocations, which are associated with distinct subtypes of leukemia. The identification of these rearrangements provides critical diagnostic and prognostic information, which may contribute to the selection of specific anti-leukemic therapy. The translocation t(9;22), the equivalent of the BCR/ABL rearrangement, is associated with a poor prognosis. We therefore used RT-PCR to detect this molecular event in a prospective study including 890 children. 673 of them suffered from acute lymphoblastic leukemia (ALL) at primary diagnosis and a transcription of the chimeric gene was detected in 21 of 648 with a successful analysis (3.2%). All children were treated by one of the two German multicenter childhood ALL therapy studies ALL-BFM-90 or COALL-05-92, respectively. Comparison of clinical features between BCR/ABL-positive and -negative children showed no significant differences regarding WBC, percentage of blasts, splenomegaly, hepatomegaly and age. Immunophenotypic studies at diagnosis in 21 BCR/ABL-positive children identified common ALL in 16 patients (76.2%), pre-B-ALL in four (19.0%), and an early T-lineage ALL in one (4.8%). Coexpression of myeloid antigens (CD13 and/or CD33) was observed in six of 16 common ALL patients as well as in the one child with early T-lineage ALL phenotype. The type of breakpoint (m-BCR/ABL: n = 14; M-BCR/ABL: n = 7) showed no correlation with clinical parameters. A comparison of cytogenetic and molecular data was performed in 16 positive patients and was concordant in all of them. We analyzed the response to the prednisone pretreatment and found a higher incidence of poor responders among the BCR/ABL-positive children. Regarding the event-free survival (EFS) of BCR/ABL-positive (0.53) and -negative patients (0.79) after a follow-up of 2 years, significant differences (P < 0.05) between both groups could be demonstrated.

Adolescent↗
PubMed1995

Secondary acute myeloid leukemia with translocation (4;11) and MLL/AF4 rearrangement in a 15-year-old boy treated for common acute lymphoblastic leukemia 11 years earlier.

Secondary acute myeloid leukemia occurring in a 15-year-old boy 11 years after initial treatment of a common lymphoblastic leukemia (c-ALL) is described. Initial complete remission was terminated after 4 years by an isolated testicular relapse, followed by first bone marrow relapse within 18 months. After he achieved remission again, an allogeneic bone marrow transplantation from his HLA-identical brother was performed. Five years and 9 months later, the patient developed thrombocytopenia, leukopenia, and anemia, but bone marrow biopsies at this time demonstrated only myelofibrosis, with no blast cell population present. A polymerase chain reaction assay of a peripheral blood sample recognized the mRNA fusion region for the MLL/AF4 rearrangement, i.e., the molecular equivalent of the translocation (4;11)(q21,q23). Four weeks later, a blast cell population with AML-M1 morphology according to the FAB classification appeared in the bone marrow, and translocation (4;11) was detected by cytogenetics. Thus, secondary leukemias with chromosomal 11q23 rearrangement can develop after a long latency period and can be diagnosed earlier with the PCR technique.

Acute Disease↗
PubMed1995

Characterization of chromosome 8 abnormalities by fluorescence in situ hybridization in childhood B-acute lymphoblastic leukemia/non-Hodgkin lymphoma.

Using fluorescence in situ hybridization (FISH), we studied chromosome 8 abnormalities in 30 children with mature B-cell acute lymphoblastic leukemia (B-ALL) or B-cell non-Hodgkin lymphoma (B-NHL). FISH was performed on metaphase spreads and interphase nuclei with a whole chromosome 8 painting probe. Fifteen patients were studied retrospectively after metaphases from the malignant cell specimen had already been G-banded. When interphase nuclei were examined, FISH was able to confirm t(8;14)(q24;q32) in all nine patients positive by previous G-banding. FISH, however, was positive in metaphase spreads from only seven patients. Another 15 patients were included in a prospective study. In six of them (40%), a translocation involving chromosome 8 was shown by a split small segment (8q24-8qter) on interphase nuclei. Analysis of metaphase spreads showed only three positive cases each by FISH or G-banding, respectively, with corresponding results in two patients. By interphase FISH, trisomy of chromosome 8 also was detectable. In three patients shown by G-banding to have trisomy, interphase FISH study showed high scores of three chromosome 8 signal positive cells. There was no cross-hybridization to other chromosomes interfering with FISH analysis. FISH analysis on interphase nuclei using a whole chromosome 8 hybridization probe will supplement and can be more sensitive than metaphase cytogenetic techniques for detection of chromosome 8 rearrangements in B-ALL/NHL.

Adolescent↗
PubMed1995

12q13, a new recurrent breakpoint in acute non-lymphoblastic leukemia.

The karyotypes of 312 successfully analyzed samples of children with acute non-lymphoblastic leukemia (ANLL), which were sent to us by 72 German hospitals, were examined in order to find new recurrent chromosome abnormalities of possible clinical relevance. Whereas most of the patients had one of the specific aberrations of ANLL or a normal karyotype, random numerical or structural changes were found in 61 children (20%). Four of them showed an abnormality involving band 12q13: t(12;17)(q13;q21), t(12;21)(q13;q21), t(2;12)(p13;q13), and t(5;12)(p11;q13). Despite the fact that FAB subtypes were different (M0, M1 M6, AHL), the blasts of all patients were characterized by immaturity and were difficult to classify. The breakpoint 12q13 might be of clinical importance in ANLL, because the four patients in our study, as well as the 21 patients with this aberration found in the literature, had a very poor prognosis.

Child↗
PubMed1995

Comparison of DNA aneuploidy, chromosome 1 abnormalities, MYCN amplification and CD44 expression as prognostic factors in neuroblastoma.

A comparison of the prognostic impact of five molecular variables in a large series was made, including tests of their nonrandom association and multivariate analysis. Molecular data were available for 377 patients and MYCN amplification, cytogenetic chromosome 1p deletion, loss of chromosome 1p heterozygosity, DNA ploidy and CD44 expression were investigated. Their interdependence and influence on event-free survival was tested uni- and multivariately using Pearson's chi 2-test, Kaplan-Meier estimates, log rank tests and the Cox's regression model. MYCN amplification was present in 18% (58/322) of cases and predicted poorer prognosis in localised (P < 0.001), metastatic (P = 0.002) and even 4S (P = 0.040) disease. CD44 expression was found in 86% (127/148) of cases, and was a marker for favourable outcome in patients with neuroblastoma stages 1-3 (P = 0.003) and 4 (P = 0.017). Chromosome 1p deletion was cytogenetically detected in 51% (28/55), and indicated reduced event-free survival in localised neuroblastoma (P = 0.020). DNA ploidy and loss of heterozygosity on chromosome 1p were of less prognostic value. Most factors of prognostic significance were associated with each other. By multivariate analysis, MYCN was selected as the only relevant factor. Risk estimation of high discriminating power is, therefore, possible for patients with localised and metastatic neuroblastoma using stage and MYCN.

Aneuploidy↗